Pallid Sturgeon Pallid Sturgeon: biology & techniques for monitoring a large river fish Actinopterygii (ray finned fishes) Acipenseriformes (Sturg. & paddlefishes) Acipenseridae (Sturgeons) Scaphirhynchinae Scaphirhynchus albus Scaphirhynchus: Greek, skaphe, eos = boat + Greek, rhyngchos = albus: From the word albus, meaning white Pallid sturgeon Identified in 1905 They are unique among bony fishes because the skeleton is almost entirely cartilaginous Bony scutes as armor Long livedmaximum age 50+ Up to 5 feet long Benthic orientation adapted for swift velocities Life history Reproductive biology Reproduce at 9 years old (~800 mm) Reproduce in 2 3 year intervals (Males) or 3 5 year intervals (Females) Switch to piscivory ~ 600 mm 1
Preglacial period Postglacial period Pallid sturgeon distribution Lake sturgeon Pallid sturgeon The combined Missouri Mississippi River, at 3,709 miles, the fourth longest river in the world, after the Nile, Amazon, and Yangtze Shovelnose sturgeon Shovelnose sturgeon distribution Lake sturgeon distribution 2
Reproductive cycle Spawning migration Eggs Embryo hatch & drift Timeline Pre 1900s Embryos are intercepted & rear in shallow water habitats 3
Channelizing The River Wing Dike Construction at Indian Cave Bend, Nebraska, Missouri River, 10 1935, Source: USACE Indian Cave Bend on the Missouri River near river mile 517, about 18 miles upstream from Rulo, Nebraska, illustrating the river before (1934; top photo) and after (1935, 1946, and 1977) the construction of brush dikes that narrowed and channelized the river. https://www.nap.edu/read/13019/chapter/4#32 Channelizing The River Elevated Flows Sourece:https://lh3.googleusercontent.com/CqCwB6CLbVPUjmpPjjM2aqNWlJktKuqYu_0ixajc5dR9zqCqBrMfhGncUJWIFv azpl431swywwwcwvvjsgeuhpdziu7ggp9qehctjcwewgboclb6ueph31lyhathkwtxvpfcqwjeiam Dynamic Habitat Embryo hatch & drift 4
Timeline 1930s-1960s Pre 1900s 1912 1944 1. Fort Peck Dam Additional Dams 3. Garrision Dam Fort Peck Dam Additional Dams 4. Oahe Dam 6. Big Bend Dam 2. Fort Randall Dam 5. Gavins Point Dam Fort Peck Dam Additional Dams THE MISSOURI RIVER TOO THIN TO PLOW & TOO THICK TO DRINK 5
Sediment delivery Milk River Upstream dams allow sediment to settle out & increase water clarity https://www.nap.edu/read/13019/chapter/4#37 Timeline Endangered Species Pre 1900s 1912 1944 1990 Fish & Birds Timeline Endangered Species Pre 1900s 1912 1944 1990 2000s 6
Recovery program Habitat Restoration "Channels of the Big Muddy" flickr photo by Plains and Prairie Potholes Landscape Conservation https://flickr.com/photos/plainsandprairielcc/8044354882 shared under a Creative Commons (BY) license Habitat Restoration Restoration "Dalbey Bottoms progress on March 29, 2012" flickr photo by Kansas City District https://flickr.com/photos/usace-kcd/6922442274 shared under a Creative Commons (BY) license Floodplain connectivity Floodplain connectivity 7
2003: Catch-Effort Monitoring Catch-effort based population monitoring Began in 2003 2 Seasons Sturgeon season (October to June) Fish community season (June to October) Standardized sampling Multiple gears Active & passive Capture varying sizes Sampling frame Sampling grain Bends are defined as three contiguous habitat units, a channel cross over, inside bend, & outside bend Sampling gears: Sturgeon season 1. Standard gears for Segments 1 4 1. Trammel net 2. Otter trawl 3. Trotlines Bends are defined as three contiguous habitat units, a channel cross over, inside bend, & outside bend Missouri River 8
Sampling gears: Sturgeon season 1. Standard gears for Segments 5 7 1. Trammel net 2. Gill net 3. Otter trawl 4. Trotlines Sampling gears: Sturgeon season 1. Standard gears for Segments 8 14 1. Trammel net 2. Gill net 3. Otter trawl 4. Trotlines Missouri River Missouri River Sampling gears: Fish community 1. Standard gears for Segments 1 4 1. Mini fyke net 2. Trammel net 3. Otter trawl 4. Trotlines 5. Pallid Sturgeon gear of choice Sampling gears: Fish community 1. Standard gears for Segments 5 7 1. Mini fyke net 2. Trammel net 3. Otter trawl 4. Trotlines 5. Pallid Sturgeon gear of choice Standard gear to catch more sturgeon Sampling gears: Fish community 1. Standard gears for Segments 8 14 1. Mini fyke net 2. Trammel net 3. Otter trawl 4. Trotlines 5. Push trawl 6. Pallid Sturgeon gear of choice Sturgeon & fish community differences No Gill nets stressful in warmer water Fyke nets in fish community Push trawl in lower segments 9
Fish size & gears Otter trawl Experimental gill nets Mini fyke-net Throat Box Lead Panels vary in size: 1, 1.5, 2, 4 Size selective catch Trotlines Good for mobile small bodied fishes. Typically set overnight. 10
Trammel nets Drifted downstream Data collected Environmental variables Velocity, depth, turbidity, temperature Habitat type Pallid Sturgeon Length, weight, tagged, genetics, blood Timeline Endangered Species Pre 1900s 1912 1944 1990 2000s Current Adaptive Management 2013: Recovery play includes an adaptive management plan you need to monitor 11
Problem Current catch effort based monitoring may not be sufficient to meet recovery objectives, estimate metrics needed to assess listing status, & support adaptive management. Modified monitoring program Capture recapture program 1. Bends sampled for 4 days (3 occasions) 2. Captured sturgeon marked Floy tag PIT tag Capture recapture Shovelnose sturgeon are Floy tagged only need tag retained for a short period of time Pallid sturgeon are PIT tagged less likely to lose tag Use closed population capture recapture estimators to estimate bend level abundance Multiple occasions Day 1 Day 2 Day 3 Capture histories Cap Hist. 40 43 100 84 108 Captured day 1 only 110 9 9 Captured day 1 and day 2 101 3 7 Captured day 1 and day 3 111 1 1 Captured days 1, 2, & 3 010 127 212 Captured day 2 only 011 8 5 Captured day 2 and day 3 001 114 208 Captured day 3 only Capture histories Estimate capture probability By size Environmental covariates (flow) Bend Caught Abundance P1 P2 P3 40 348 2005 0.048 0.073 0.063 43 553 4601 0.027 0.05 0.048 12
ECOLOGICAL CONTEXT "Sub Adult Pallid Sturgeons" flickr photo by U.S. Fish and https://flickr.com/ph shared unde 13